A number of Britons are missing following the devastating typhoon in the Philippines, Foreign Secretary William Hague has confirmed.
The news that a "number of British nationals remained unaccounted for" came as it emerged that donations to the UK's Typhoon Haiyan charity appeal have reached £33 million.
Among those feared dead is Colin Bembridge, 61, from Grimsby, who was staying with his Filipino partner Maybelle, 35, and their three-year-old daughter Victoria near the city of Tacloban when the storm struck.
Channel 4 News said Mr Bembridge had been visiting his girlfriend's relatives and had hired a beach house in Baybay, one of the ravaged coastal villages.
The mother of Mr Bembridge's partner, 79-year-old Lydia, showed the programme the wreckage of the beach house where her daughter and granddaughter had been staying and said they had not been seen since the powerful typhoon struck eight days ago.
A Foreign Office spokesman said Mr Hague spoke on the phone to Philippines Secretary for Foreign Affairs Albert Ferreros Del Rosario this afternoon to offer his condolences.
"The Foreign Secretary confirmed that a number of British nationals remained unaccounted for," he added.
"He asked that every possible assistance be given to any British people caught up in the disaster."
Earlier today an RAF plane carrying heavy duty vehicles and emergency medical supplies arrived in the Philippines as part of the UK's emergency response to the disaster.
The huge C-17 transport plane touched down in Cebu province to deliver two JCB diggers, two Land Rovers and a forklift truck shortly after 8am GMT after leaving RAF Brize Norton in Oxfordshire yesterday morning.
The logistical equipment will help with the distribution of aid, clear debris left by the storm and with reconstruction work to help the millions of people who have been displaced.
The news of the huge response to the Disasters Emergency Committee's (DEC) appeal comes after the BBC announced its annual Children in Need fundraiser has raised a record £31 million for disadvantaged children and young adults in the UK.
Speaking on behalf of the 14 UK charities which make up the DEC, its chief executive Saleh Saeed said: "The generosity of the public is yet again surpassing all expectations."
David Cameron also announced the Government is to give an extra £30 million in aid, bringing the total amount to £50 million.
Speaking at a press conference in Sri Lanka ahead of the Commonwealth summit, the Prime Minister said the scale of the disaster is "becoming clearer every day".
A C-130 Hercules aircraft, described as the "work horse" of the RAF fleet, will also be sent over to help carry aid workers to areas that have so far been difficult to reach.
And British Airways said it was offering aid agencies including Oxfam, Save the Children and Unicef an aircraft to fly emergency aid and supplies to the disaster zone.
The Boeing 747 freighter, which has a capacity for up to 120 tonnes of cargo, is scheduled to leave from Stansted Airport in Essex on Monday.
Typhoon Haiyan - said to be the strongest ever to make landfall - has made roads impassable and left airports out of action, severely hampering relief efforts.
Asif Ahmad, British ambassador to the Philippines, was at the airport to meet this morning's delivery.
He said: "The significance of this load is that it is heavy machinery: bulldozers, Land Rovers, machines that can actually push through the debris that is blocking aid now.
"This is vital equipment because the Philippine military and others have not been able to bring this material here."
Five UK Government flights have now delivered aid packages and at least seven more are planned to leave. These have so far delivered 14,988 shelter kits, 17,369 tarpaulins, 11,230 hygiene kits, 5,925 jerry cans and nine 4x4s.
Mr Cameron said: "Today, I can announce we are providing another £30 million to support the UN and the Red Cross emergency appeals and we are also supplying an RAF C-130 Hercules aircraft to help ensure aid workers can move between the worst affected areas and get aid to those who need it.
"A week after Typhoon Haiyan hit, the scale of the disaster is becoming clearer every day - over 3,600 dead, nearly 12 million affected.
"I'm proud of the fact that the UK has taken the lead in international relief with rapid response of warships, aircraft and equipment."
The funding will be used to deliver vital supplies to more than 500,000 victims of the disaster and support UN and Red Cross teams working on the ground as they co-ordinate the international relief effort.
A 12-strong team of British doctors, surgeons and paramedics are already in the devastated Asian country helping to treat survivors of the typhoon.
Royal Navy aircraft carrier HMS Illustrious is also being sent to replace HMS Daring, which has already been deployed to the Philippines.
The latest death toll given by Mr Cameron is an increase of more than 1,000 on estimates made by the country's civil defence agency earlier this week.
But some officials estimate that the final toll, when the missing are declared dead and remote regions are reached, will be more than 10,000.
Jane Cocking, of Oxfam, said: "Oxfam's teams are already on the ground and delivering aid to some of the worst affected areas.
But we urgently need to bring more supplies in and this British Airways flight will enable us to do just that, helping us to provide emergency supplies and shelter to thousands of people who are in desperate need."
Robbie McIntyre, humanitarian officer at Save the Children, said: "This flight provides us with an invaluable opportunity to get vital water, sanitation and hygiene supplies to those in the most desperate need. We are sending equipment that will be able to provide over 310,000 litres of safe drinking water as well as equipment to support sanitary toilet facilities.
"During disasters such as this it's always a challenge to get equipment of this type into the areas of most need, so we are hugely grateful to British Airways for giving us space on this flight."